Question

(a+b)^4+(a2-b2)^2+(a-b)^4

Answer 1

(a+b)4+(a2-b2)2+(a-b)4

=(a+b)4+(a+b)2(a-b)2+(a-b)4

=(a+b)4+2(a+b)2(a-b)2+(a-b)4-(a+b)2(a-b)2

=【(a+b)2+(a-b)2】2-(a2-b2)2

=（2a2+2b2）2-(a2-b2)2

=（2a2+2b2+a2-b2）（2a2+2b2-a2+b2)

=(3a2+b2)(a2+3b2)